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利用激光熔覆制备技术,通过涂层成分设计与梯度制备方法,在Ti-6Al-4V钛合金基体上制备界面冶金结合的生物陶瓷梯度涂层。主要利用金相显微、扫描电镜、硬度计和X-射线衍射等分析手段,对制备梯度涂层的熔覆工艺、组织结构、相组成及其形成机理进行了研究。实验结果表明:梯度涂层的成分组成分别为第一层Ti粉80%、CaCO3和CaHPO4为19%、Y2O3为1%;第二层Ti粉40%、CaCO3和CaHPO4为59%、Y2O3为1%;第三层Ti粉为0%、CaCO3和CaHPO4为99%、Y2O3为1%。在优化激光制备工艺参数条件下,成功在钛合金表面制备出了界面冶金结合、无裂纹缺陷的类生物骨组织结构的梯度涂层。涂层中的主要生物陶瓷相是CaTiO3、CaP及Ca3(PO4)2相。由于采用了钛成分含量的梯度变换设计,避免了基体和涂层及层与层之间材料因热膨胀系数、弹性模量差异过大而造成结合界面的孔洞、裂纹现象,同时保证了钛合金基体与生物骨涂层之间形成了牢固的冶金结合。
By using laser cladding technology, interface metallurgical bonded bio-ceramic gradient coating was prepared on Ti-6Al-4V titanium alloy substrate by coating composition design and gradient preparation method. The microstructure, microstructure, phase composition and formation mechanism of graded coating were studied by means of metallographic microscope, scanning electron microscopy, hardness tester and X-ray diffraction. The experimental results show that the composition of gradient coating is 80% of the first layer of Ti powder, 19% of CaCO3 and CaHPO4, 1% of Y2O3; the second layer of 40% of Ti powder, 59% of CaCO3 and CaHPO4, Y2O3 of 1 %; Third Ti powder is 0%, CaCO3 and CaHPO4 is 99%, Y2O3 is 1%. Under the condition of optimizing the parameters of laser preparation, the graded coating of biological-like bone tissue with interface metallurgical bonding and no crack defect was successfully prepared on the surface of titanium alloy. The main bioceramic phases in the coating are CaTiO3, CaP and Ca3 (PO4) 2 phases. Due to the adoption of the gradient transformation design of the titanium component content, it avoids the phenomena of holes and cracks in the bonding interface caused by the thermal expansion coefficient and the large difference of the elastic modulus between the substrate and the coating and between the layers, and ensures the titanium alloy substrate A strong metallurgical bond is formed with the biological coating.